The present invention relates to a capillary array electrophoresis device for separating a sample such as fluorescence labeled DNA and detecting, identifying and analyzing a base sequence, a base length and so on of the sample according to electrophoresis in a capillary, and more particularly, to a capillary array to be incorporated into the capillary array electrophoresis device and a capillary array photodetector for detecting emission from the sample migrating through the capillary array.
Capillary electrophoresis has been utilized for determination of DNA base sequences and DNA base lengths. In the capillary electrophoresis, a sample containing DNA as a measuring object is injected into a capillary made of glass or the like and filled with a polyacrylamide gel or the like, and then a voltage is applied to each of the ends of the capillary. The synthetic DNA in the sample migrates through the capillary to be separated into fragments according to molecular weights thereof and so on, and then a DNA band is generated in the capillary. A fluorescent dye molecule is bonded to each of the synthetic DNA fragments, and emission measuring means measures emission from each of the fragments by way of laser beam irradiation, to thereby determine base sequences, base lengths and the like of the synthetic DNA fragments from the measured fluorescent spectra.
U.S. Pat. No. 5,582,705 discloses a multi-focus system, which is a variation of a system of irradiating a plurality of capillaries with light. In the system, laser beam is irradiated on a capillary at one end or capillaries on both ends of a capillary array comprising a plurality of capillaries aligned in parallel to each other on a planar substrate, and the laser beam is propagated to adjacent capillary or capillaries one by one to ultimately travel across the capillary array so that a photodetector detects emissions generated in the capillary array. Each of the capillaries is applied with a polymer coating, but the polymer coating is not applied at part of the capillaries to be irradiated with a laser beam.
There have been proposed irradiation systems other than the multi-focus system, such as a scanning system wherein a plurality of capillaries to scan each of the capillaries is irradiated with a laser beam (Nature, 359 (1992)), a multi-beam system wherein each of a plurality of capillaries is irradiated with a laser beam (Analytical Chemistry, 65, 956 (1993)), and a batch irradiation system (Analytical Chemistry, 66, 1424 (1004)) wherein a plurality of capillaries are subjected to a batch irradiation with a laser beam that is spread by a cylindrical lens in a direction along which the capillaries are aligned. The multi-focus system has the advantage of excellent detection sensitivity for DNAs as compared with the above systems.